Trio of glass anal plugs is great for training or re-training those special muscles for better control. strength and endurance. It's a pelvic floor workout with many sexual health benefits. Made from durable tempered borosilicate glass. each plug is a different size. The small plug is 4.5 in. by 1.15 in.; medium is 4.75 in. by 1.35 in.; and large is 5.75 in. by 1.55 in. Chill or warm glass for even more stimulation.